[InlineCost] Disable cost-benefit when sample based PGO is used (#86626)

#66457 makes InlineCost to use cost-benefit by default, which causes
0.4-0.5% performance regression on multiple internal workloads. See
discussions https://github.com/llvm/llvm-project/pull/66457

. This pull
request reverts it.

Co-authored-by: helloguo <helloguo@meta.com>